

var Type = {};//js 类型检测 typeof

for (var i = 0,type;type = ['String','Array','Number'][i++];){
    (function(type){
        Type['is' +type] = function(obj){
            
           return Object.prototype.toString.call(obj) == "[object " + type+ "]"; 
        }
    })(type)
}
console.log(Type.isString('a'));
console.log(Object.prototype.toString.call(464) );